Hook-shaped gripper point

ABSTRACT

A hook-shaped yarn takeup gripper point having a protuberance formed on a first side of the free leg of the hook, the end of the protuberance away from the tip of the gripper point forming a trailing edge which extends substantially perpendicular to a central plane passing through both the main leg and the free leg of the gripper point. A spring operated flap in the main leg holds a yarn against the free leg, and hence against the said edge.

United States Patent Heinz Maassen Dulken, Germany 861,558

Sept. 29, 1969 May 1 l, 1971 The Firm of Jean Gusken Dulken, GermanySept. 27, 1968 Germany lnventor Appl. No. Filed Patented AssigneePriority HOOK-SHAPED GRIPPER POINT 3 Claims, 3 Drawing Figs.

US. Cl

Int. Cl. Field of Search llll 3,578,031

[ References Cited UNITED STATES PATENTS 2,928,427 3/1960 Flamand139/122 2,960,118 11/1960 Ancet et al. 139/122 3,299,910 1/1967 Flamand139/122 Primary Examiner-Henry S. J audon Attorney-Larson and TaylorABSTRACT: A hook-shaped-yarn takeup gripper point having a protuberanceformed on a first side of the free leg of the hook, the end of theprotuberance away from the tip of the gripper point forming a trailingedge which extends substantially perpendicular to a central planepassing through both the main leg and the free leg of the gripper point.A spring operated flap in the main leg holds a yarn against the freeleg, and hence against the said edge.

HOOK-SHAPED GRIPPER POINT BACKGROUND OF THE INVENTION This inventionrelates to hook-shaped yarn takeup gripper points for tucking in weftyarn ends in gripper looms. In particular, it relates to a new andimproved arrangement for providing a more secure engagement of the yarnby the gripper point.

It is known to provide hook-shaped gripper points with means such asclamps for holding the yarn against the free leg of the hook. However,with known arrangements it often happens in practice that due toexcessive unforeseen yarn tension, the yarn slips out of engagement withthe gripper point and is lost. The problem cannot be solved by simplymaking sure that a completely uniform yarn tension is applied to theyarn at all times. Irregularities in tension occur from faulty bobbinwindings and the uneven friction, especially in the case of fancy yarns,between weft yarn and bobbin and on the yarn guide elements. MOreover,there are normal changes in tension during normal operation, for exampleduring pulloff, and tension is different for a full spool as comparedwith an empty spool. Another problem to be considered is that the clampholding the weft yarn in the jaw of the hook slips through more easily,the deeper the hook has been pulled into the hook jaw as the clampingforce of the clamp diminishes in proportion to the distance of the yarnfrom the pivot point of the clamp on the body of the hook.

Thus, there exists a need for a gripper point of the type describedwhich will hold the yarn securely even as the tension applied to theyarn varies.

SUMMARY OF THE INVENTION Thus, it is a purpose of this invention toprovide a new and improved hook-shaped yarn takeup gripper point, of thetype described, which overcomes disadvantages of such gripperpointsknown heretofore. In particular, it is a purpose of this invention toprovide a gripper point of the type described which securely holds theyarn, regardless of variations in tension applied to the yarn.

This purpose of the present invention is achieved by providing, in ahook-shaped yarn takeup gripper point of the type described, aprotuberance formed on and extending sideways from a fist side of thefree leg of thehook, said protuberance having a trailing edge on theside thereof facing away from the tip of the gripper point, which edgeextends outwardly substantially perpendicular relative to a centralplane passing through both the main leg and the free leg. With thisarrangement, the yarn is held securely against the jaw of the hookadjacent said edge. A spring-operated flap yarn holder located in themain leg of the gripper point engages the free leg to hold the said yarnagainst the free leg and, in particular, against said edge. Thisarrangement prevents slipping of the yarn in two ways. On the one hand,the yarn is drawn more deeply into the jaw of the hook as it lies aboutthe rear edge of the protuberance, whereby the friction between the yarnand the hook is increased. Secondly, the protuberance with its said rearedge projecting substantially at right angles from the said centralplane controls the location of the yarn relative to the springoperatedmeans so that the flap means always operates on the yarn at the samedistance from the pivot axis of the flap means.

Thus, it is an object of this invention to provide a new and improvedhook-shaped yarn takeup gripper point of the type described.

It is another object of this invention to provide a gripper point of thetype described having a protuberance formed on the free leg thereof,said protuberance having a rear edge which is substantiallyperpendicular to a central plane through the legs of the gripper pointand which engages the yarn for improving the securement of the yarn,notwithstanding variations in tension. y j

It is another object of this invention to provide a gripper point of thetype described having a protuberance located on one side of the free legfor controlling the point at which the spring-operated flap meansengages and holds the yarn.

Other objects and the intended advantages of the present invention willbecome apparent from the detailed description to follow together withthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS There follows a detailed descriptionof a preferred embodiment of the invention to be read together with theaccompanying drawings. However, the drawings and the description areprovided only to illustrate a preferred embodiment of the invention.

FIG. 1 is a side elevational view of a hook-shaped yarn takeup gripperpoint constructed in accordance with the present invention, with partsshown in cross section.

FIG. 2 is a partial elevational view viewed from the left sid of FIG. 1.

FIG. 3 is an enlarged partial perspective view illustrating the end ofthe hook-shaped yarn takeup gripper point.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to thedrawings, like numerals represent like elements throughout the severalviews.

The yarn takeup gripper point of the present invention includes a mainbody portion which at the upper end thereof (as viewed in the FIGS.)includes a hook-shaped portion with a main leg 1, a tip 9 and a free leg4. Formed within this main leg In accordance with a main feature of thepresent invention, the free leg 4 has formed thereon a protuberance 7 onthe first side 10 thereof. This first side is defined as that sideagainst which the yarn 5 lies. This protuberance 7 includes a rear edge(that is, on the side of the protuberance away from the tip 9) which isformed with a rear edge 8, which edge is substantially perpendicular toa central plane of the gripper point passing through both legs 1 and 2.

This protuberance 7 with its said rear edge 8 catches the yarn and pullsthe same into the jaw of the hook. The yarn now lies about thisrelatively sharp rear edge 8, whereby friction between the hook and theyarn is considerably increased. Moreover, the protuberance 7 preventsthe yarn 5 from being pulled farther up into the jaw of the hook wherethe force applied by the flap 2 would be smaller. Thus, slippage of theyarn from the hook is avoided, notwithstanding variation, especiallyincreases in tension.

Although the invention has been described in considerable detail withrespect to a preferred embodiment thereof, it will be apparent that theinvention is capable of numerous modifications and variations apparentto those skilled in the art, without departing from the spirit and scopeof the invention.

I claim:

1. In a hook-shaped yarn takeup gripper point for tucking in weft yarnends in gripper looms, the hook including a main leg and a free leg, andsaid gripper point including means for clamping the yarn end against theinside of the free leg of the hook, the improvement comprising aprotuberance on a first side of the said free leg, said protuberancehaving an edge on the side thereof away from the tip of the gripperpoint, said edge extending outwardly from the first side of the gripperpoint, whereby yarn drawn through the hook passes along said first side,around said edge and across the inside of the free leg to a second sideof the free leg.

2. The invention of claim 1, wherein said edge is substantiallyperpendicular to a central plane of the hook passing through both ofsaid legs.

3. The invention of claim 2, wherein said clamping means comprises aflap located in the main leg and urged by resilient means against thefree leg to hold the yarn against said free leg and hence against saidedge.

1. In a hook-shaped yarn takeup gripper point for tucking in weft yarnends in gripper looms, the hook including a main leg and a free leg, andsaid gripper point including means for clamping the yarn end against theinside of the free leg of the hook, the improvement comprising aprotuberance on a first side of the said free leg, said protuberancehaving an edge on the side thereof away from the tip of the gripperpoint, said edge extending outwardly from the first side of the gripperpoint, whereby yarn drawn through the hook passes along said first side,around said edge and across the inside of the free leg to a second sideof the free leg.
 2. The invention of claim 1, wherein said edge issubstantially perpendicular to a central plane of the hook passingthrough both of said legs.
 3. The invention of claim 2, wherein saidclamping means comprises a flap located in the main leg and urged byresilient means against the free leg to hold the yarn against said freeleg and hence against said edge.